Motion transmitting and speed changing devices having an input member and an output member, the latter being driven by a gear means through a coupling which transforms eccentric motion to rotary motion and the former driving the gear means through and eccentric, are known in the art. Examples of motion transmitting devices in which the gear means meshes with meshing elements having limited movement are illustrated in U.S. Pat. Nos. 4,023,440 and 4,194,415 granted May 17, 1977, and Mar. 25, 1980, respectively. These drives are known as "Quadrant Drives" becauses the driving engagement of the gear means and the meshing elements is substantially through an arc of 90.degree.. In these patents, the meshing elements are linked together, and ovoid holes in one or more datum members or capturing plates flanking the gear means comprise the movement limiting means. Drives of the type described generally use an Oldham coupling to convert the eccentric output to the rotary motion.
A suggestion has been made in a motion transmitting device to support an output shaft in bearings disposed in a cup-like portion of an input shaft which is in turn journalled in a bearing supported by the housing, the output shaft being driven by a coupling which includes a generally circular disc-like rotor attached to the output shaft, and driven by pins extending from a rotor member in turn driven by an eccentric gear which provides a reduction drive.